Aogashima in 3D: The Village Inside a Volcano

An island in the Philippine Sea, administratively part of Tokyo, where roughly a hundred and seventy people live inside the caldera of an active volcano that has a second cone growing in the middle of it. Here is how to explore Aogashima in 3D from your iPhone.

Aogashima is the southernmost inhabited island of the Izu chain, about 360 kilometres south of Tokyo, and it belongs to Tokyo Metropolis — which means the same city government that runs Shinjuku also runs a village on the floor of an active volcano.

The island is essentially one volcano with its top blown off. What is left is a ring of cliffs enclosing a basin, and inside that basin sits a second, younger cone called Maruyama, complete with its own crater. A caldera within a caldera. Around a hundred and seventy people live there, most of them in the settlement on the northern rim and on the basin floor.

Getting there is difficult enough that most people never do. You can explore Aogashima today, in full 3D with live Street View, right from your phone.

What makes Aogashima special

The shape is the whole thing. Aogashima’s outer wall rises straight from deep water to a rim several hundred metres up, with almost no coastal shelf and no natural harbour worth the name. Inside that wall the ground drops into a green bowl, farmed and forested, and then rises again in the middle where Maruyama sits.

That inner cone is the youngest part of the island. The eruption that built it, in the 1780s, is also the reason there is a gap in the island’s history: the population was evacuated, many did not survive the eruption, and the island stayed empty for roughly fifty years before people returned and rebuilt. The village today lives with that as ordinary background rather than legend.

Geothermal heat is still close to the surface. Islanders cook using steam vents on Maruyama’s flank, and there is a sauna and bathing complex heated the same way. Because there is no significant light pollution for hundreds of kilometres in any direction, the night sky over the caldera is exceptional.

How to explore Aogashima in 3D

This is where MAPAS comes in. Street View coverage on an island this remote is limited, so the terrain view carries most of the tour — which suits Aogashima perfectly, because the terrain *is* the attraction.

For a first run, try this order:

1. Search for Aogashima, Tokyo and switch to 3D so the island lifts out of the Philippine Sea as a single steep block.
2. Orbit the outside first, low over the water, to see how abruptly the cliffs rise and how little flat ground exists at sea level.
3. Come over the northern rim, where the village and the school sit, and look down into the basin.
4. Drop into the caldera and circle Maruyama, the inner cone, to see the crater inside the crater from directly above.
5. Follow the single road that switchbacks from the port at Sanbanzawa up over the rim and down into the bowl.
6. Pull back far enough to see Hachijōjima to the north, the island the helicopter and ferry come from.

Beyond the caldera floor

• Maruyama — the inner cone, ringed by a walking trail, with steam vents on its slopes still hot enough to cook with.
• Ōtonbu — the highest point on the outer rim, and the standard viewpoint down into the whole basin.
• Sanbanzawa port — the concrete landing on the northeast coast, and the reason ferries are cancelled so often.
• The geothermal sauna — a bathhouse and cooking area running on volcanic steam rather than fuel.
• The night sky — genuinely dark, with the Milky Way visible over the rim on a clear night.

Why a caldera within a caldera happens

Seen flat on a map, Aogashima is an oval with a smudge in the middle. Seen in 3D, the sequence is obvious.

First a volcano built itself up from the seabed. Then a large eruption emptied the magma chamber beneath it faster than the summit could be supported, and the top collapsed inward, leaving a ring of cliffs around a basin — that is a caldera, and it is a collapse feature rather than a blast crater. Over time, soil built up on the floor and vegetation took hold, which is why the inside is green and the outside is grey rock.

Then the system recharged and erupted again, this time from a vent on the caldera floor, and built Maruyama up from the middle with its own small crater on top. Tilting the terrain shows the two scales stacked: an old, wide collapse with a young, narrow cone standing inside it. It is one of the clearest examples of the process anywhere, mostly because the whole thing is small enough to take in at once.

Before you go

Aogashima is not a day trip, and it is not really a casual one either. Almost nothing is open late, there is one shop, cash is essential, and mobile coverage is workable but not universal. Visitors are expected to behave like guests in a very small community, because that is exactly what they are.

The volcano is monitored and currently quiet, but it is classed as active, and evacuation planning is a real part of island life rather than a formality. Weather is the practical constraint: typhoon season through late summer and early autumn disrupts both the ferry and the helicopter, and winter brings its own swell.

Common questions

How many people live on Aogashima?

Around a hundred and seventy, making it one of the least populated municipalities in Japan, with a single village, one school and one shop.

Can you climb into the inner crater?

There are walking trails on and around Maruyama, and the geothermal cooking area sits on its flank. Conditions and access can change, so follow the village’s signage rather than an old trip report.

Is MAPAS free to use?

Yes. It is free on the App Store, needs no sign-up before you start exploring, and works on iPhone and iPad.

No helicopter seat, no cancelled ferry, no waiting out a typhoon on Hachijōjima. Just an island that is a volcano inside a volcano, laid out in three dimensions where you can fly straight over the rim.

Open MAPAS and drop into the Aogashima caldera from above.